Surge capacity mechanical ventilation during an influenza pandemic requires devices capable of positive pressure ventilation (“PPV”) and delivery of positive end expiratory pressure (“PEEP”). The duration of disease may last from days to weeks, and mechanical ventilation may be required for greater than one week. One of the most dangerous results of a severe influenza infection is acute respiratory distress syndrome (“ARDS”). ARDS, which is the most frequent severe complication of influenza, is characterized by diffuse inflammation of the lungs leading to impaired gas exchange.
Currently marketed ventilators range from costly, sophisticated machines to simple low cost transport devices. Patients with ARDS need advanced ventilators capable of PPV and PEEP to overcome the increased alveolar collapse caused by inflammation. Currently marketed full-featured machines are prohibitively expensive, fragile, and overly complex for use by less skilled personnel. Portability and durability are limited and a constant power supply is required. These features make full-featured machines unsuitable for use in field settings, rural areas, or in a large scale emergency situation such as a pandemic.
Currently marketed transport ventilators are designed to be used as a temporary bridge during patient travel to and from a full-featured ventilator. Although they are more portable than the full featured ventilators, transport ventilators are not appropriate for use in ARDS patients during a pandemic. They often do not provide PEEP, have no spontaneous assist mode and are not approved for critical care use. Inefficient use of compressed air and electricity also make them ill-suited for low-resource environments and developing nations.
Low-cost resuscitators are currently available for under two hundred dollars ($200). These devices are designed as a last resort in acute situations and require constant direct supervision. They are generally not used to support an ARDS patient for any clinically relevant length of time.
When considered on a global scale, the disparity in pandemic resources between wealthy and impoverished nations is alarming. With the majority of the world's vaccine supply already purchased by wealthy nations, coverage in developing nations may be inadequate. Many countries already face an extreme shortage of ventilators, even in the absence of a pandemic. For example, in the United States, there are approximately 205,000 ventilators for a population of 300 million. In India, where the population exceeds 1.1 billion, there are only 35,000 intensive care ventilators available. What is needed to address this disparity is an extremely low-cost ventilator, specifically tailored to meet the needs of acute respiratory distress patients in low-resource, rural and emergency environments.